Thermal developer



March 29, 1966 5 Sheets-Sheet 1 Filed Aug. 1, 1963 r w on n a i r W W 3 i v I 4 3 .ww m V 9 W 4 I 2 fl/ a 2 E J ww W W M w Mm March 29, 1966 v. c. sussm THERMAL DEVELOPER 5 Sheets-Sheet 2 Filed Aug. 1, 1963 Q "LEE? In 0e nzor- Vz'cZor C. ,sussz'n @M/ Maw .17?

orney V. C. SUSSIN THERMAL DEVELOPER March 29, 1966 5 Sheets-Sheet 5 Filed Aug. 1 1963 Invenlor VicZor 656245517? wmh ' March 29, 1966 v. c. SUSSIN 3,243,579

THERMAL DEVELOPER Filed Aug. 1, 1963' I 5 Sheets-Sheet 4.

In z/ei zz or Vi'cior Cfiuss z'n March 29, 1966 v. c. SUSSIN v THERMAL DEVELOPER 5 Sheets-Sheet 5 Filed Aug. 1, 1965 I United States Patent 3,243,579 THERMAL DEVELOPER Victor C. Sussin, Chicago, 11]., assignor to The Frederick Post (30., Chicago, 111., a corporation of Illinois Filed Aug. 1, 1963, Ser. No. 299,260 12 Claims. (Cl. 219-469) developed sheet.

Such developing operations require temperatures within a predetermined range over the contacted surface of the heated platen or cylinder.

The present invention provides a thermostatically controlled electrically heated means in which the said means is a thermally responsive actuator for thermostatically controlling its own temperature.

It is the general object of the invention to provide means to be maintained at a temperature within a controlled range by electrically powered heat, which means has an appreciable coefiicient of thermal expansion, whereby dimensional change in said means is utilized to actuate an electrical switch controlling the delivery of the electrical power.

It is a particular object of the invention to provide a rotatable hollow cylinder as such means which is heated electrically from within, of which the change in axial dimension is utilized to operate a heat-controlling switch.

Various other and ancillary objects and advantages of the invention will appear from the following description and explanation of the invention in connection with the accompanying drawings, in which:

FIG. 1 is a plan View of a planar heated platen.

FIG. 2 is a front elevation of the platen of FIG. 1, showing one form of the electrical connections using a low-voltage control circuit.

FIG. 2 is a modified circuit wherein the thermally controlled switch is in the heating circuit.

FIGS. 3 to 9 show a rotary cylindrical embodiment of the apparatus.

FIG. 3 is a front elevation of a complete apparatus.

FIG. 4 is a front elevation of a clamping guiding means as it is shown and positioned in FIG. 3.

FIG. 5 shows the structure of the heated cylinder and its mounting, partly in cross-section, and in a vertical plane through the axis.

FIG. 6 is a vertical cross-section on line 66 of FIG. 3.

FIG. 7 is a vertical cross-section taken on line 77 of FIG. 4.

FIG. 8 is a side view of the right-hand end of FIG. 5.

FIG. 9 is a cross-section taken on the inclined line 9-9 of FIG. 8, showing the adjustment for thermal control.

A planar platen form of the apparatus is shown in FIGS. 1 and 2, the principles of which can be variously incorporated in other forms as illustrated hereinbelow. FIG. 1 is a plan view of a platen to be heated with an arm extending from it.

FIG. 2 shows a fixed base or framework 10 about which is a hot platen 12 heated by electrical heating means 14 on its underside 12. Plate 12 is raised above the base 10 to which it is secured by a fixed riser plate 16. For illustrative purposes the plate 12 is shown without other support because the plate 10 has an appreciable "ice coefiicient of thermal expansion causing its free righthand edge 18 to move toward and away from the mounted left-hand edge 20 as the temperature changes. This movement is used to operate a switch by opening it when the plate is extended to a limit corresponding to a predetermined temperature, and by closing it when the plate cools to a predetermined temperature. In small units requiring relatively low wattage for the heating element the control switch may be placed in series with the heating element. In larger units requiring relatively higher wattage the control switch is in a low-voltage circuit containing a relay switch for the heating element.

As shown in FIG. 2, a switch 22 has contacts 22 and 22 in a low-voltage circuit including transformer secondary coil 23 and relay coil 24. The heating means 14 is connected to power source 26 through a master switch 26 and relay-operated switch 27. Power source 26 is also connected through switch 26 to the primary coil 28 for the secondary coil 23. The switch contact 22 is adjustably fixed relative to the fixed edge 20 of the plate 12. The contact 22 is moved by the plate edge 18, being suitably carried thereby, as on arm 30 projecting from the plate 12. The adjustable fixation of contact 22' predetermines the temperature range controlled by the thermostat which comprises the plate 12 and the switch 22.

Were the contact 22* mounted to the base 10 in the vicinity of the plate edge 18, and were the base 10 by its location and character thermally expanded as a result of heat radiated to it, the results would be variable. To avoid such variation, the contact 22 is adjustably fixed by a remote mounting substantially at the fixed edge 20 of plate 12. This is accomplished by a length of metal such as bar 32 having a coefiicient of thermal expansion which is substantially zero in the temperature range to which it is subjected in the apparatus. A suitable metal is an iron nickel alloy having 36% nickel. This alloy is substantially constant in length at temperatures from 0 to 375 F. The bar 32 is mounted at one end in the riser plate 16, with its other end 33 free. The contact 22 is adjustably positioned on the bar 32 by means indicated diagrammatically by the numeral 34.

FIG. 2 shows a modification of the electrical connections illustrated in FIG. 2. Parts carried over from FIG. 2 bear the same numerals. The heating element 14 is connected in series with the switch 22 at its fixed contacts 22 Across the switch 22 there is a capacitor 22' to prevent voltage surges damaging the switch 22. One terminal of the power line 26' is connected through a master switch 26 to the heating element 14 and the other terminal of the power line 26 is connected to the movable contact 22 of switch 22.

A hot plate such as shown in FIGS. 1, 2 and 2 may be employed by placing thereon under a suitable presser a sheet of light-printed diazotype paper, herein referred to as a print, which is subject to action of heat to develop the image.

For commercial use a heated rotary platen or cylinder is provided for contact with thermally developable prints. For effecting such contact a stationary guiding or slip sheet is provided compelling a print to contact and follow the rotating cylinder. Resilient pressing means urges the guiding sheet onto the cylinder. The guiding sheet preferably spans a major portion of the periphery of the cylinder, leaving an open arcuate portion for feeding in the print and for discharging the print which is moved with and by the cylinder slidingly past the guiding sheet. In the said open arcuate portion pick-01f means for the print is located to separate it from the cylinder.

The resilient means is in the form of a layer of resilient foam carried by stationary means holding its opposite edges so as to urge the span between them toward the cylinder. Preferably, it is part of a cylindrically curved arcuate clamp of laminated construction, including the guiding sheet at the interior and a layer of the resilient material pressing against the guiding sheet for urging the guiding sheet toward the cylinder with or without an intervening print or work sheet moving with and around the cylinder. To effect movement of the print, the friction between the print and guiding slip sheet is less than the friction between the print and the heated cylinder. A sheet of polymeric film, such as polytetrafluoroethylene, offers such slight friction. Only the first-encountered end of the guiding sheet is secured, the other being free and extending in the direction of rotation of the cylinder, thus to prevent possible wrinkling. The slight friction between the cylinder, or the print, and the guiding sheet keeps the guiding sheet taut.

The heated rotary cylinder may vary widely in construction. It has a continuous unobstructed cylindrical periphery to contact the print and switch-controlled power means to heat it. The cylinder is metallic with a useful coefficient of expansion, and is preferably a hollow cylinder to minimize heat capacity and to accelerate heatcontrol. The heating means is within the hollow cylinder. In one form, it may be an electrically resistant coating over all or substantially all of the geometrically elemental regions of the cylinder. It may be a heat-lamp within the cylinder, such as an infra-red lamp. However, the preferred heating means is a winding of electrical resistance wire as described hereinafter. The expansion and contraction of the cylinder controls the heating current.

In FIG. 3 a front view of the apparatus shows a horizontal supporting framework or base 40 carrying vertical side plates 41 and 42. A smooth hollow steel cylinder 43 is suitably mounted in the side plates for rotation. One end of the cylinder has a driven gear 44 for driving gear 45 (FIG. on shaft 46 which is suitably driven by means not shown.

The cylinder 43 is a hollow shell slipped over and in contact with a separate inner core having external electric windings for generating heat. The inner core comprises inner-most a hollow steel cylinder 48 with perforations 48' to minimize its heat capacity (see FIG. 5). Over cylinder 48 is a layer 49 of glass fiber cloth for insulation. Over the insulation is a winding of resistance wire 50. Because of greater heat loss at the ends of the rotary members, due to mountings and greater exposure, the windings are closer together at the ends, as shown, thus leading to more uniform temperature over the entire length of the outer cylinder 43. Over the windings 50 is a layer of insulating ceramic cement 51, offering a low-friction face. The outside diameter of said face is such as to fit snugly within the hollow cylinder 43 which is slipped over it. The resulting low-friction interface permits any relative sliding due to different expansions in use.

To mount the cylinder 43, only one end is fixed relative to the base 40, and the other or control end is axially movable by thermal change, relative to the base and to the fixed end. Consequently, a sliding bearing is provided at the control end.

The inner perforated cylinder 48 has within its ends circular closure discs of insulating material, designated 53 at the fixed end and 54 at the control end, each with open areas 55 (FIGS. 5 and 6) for ventilation. These discs are secured to the perforated cylinder by screws, respectively, 53' and 54. The closure discs have projecting metallic axles respectively designated 53 and 54 which function as terminals for the winding 50. Spring contact members 53 and 54 fixedly carried by andinsulated from the base 40, maintain electrical contact with pointed end of the axles 53 and 54 The outer cylinder 43 also has end closures which provide large hollow axles for suitable bearings. At the fixed end an annular closure is formed by the driven gear 44, which has an inner peripheral coaxial ring-flange 56 between the ends of cylinders 43 and 48, which cylinders are secured to said flange by screws 56.. Gear 44. has a smaller coaxial ring-form flange 57 as its axle in bearing 58 having bronze bushing 58. Bearing 58 is removably mounted in side plate 41 and its bronze bushing 58' provides a lateral bearing interface 58" between its vertical side and the side wall of gear 44. A ring 59 fits over the axle flange 57 to provide a lateral bearing interface 59 between it and the side wall of the bearing 58. A spring clip 60 in a recess in axle flange 57 positions ring 59 against the bearing 58, thus fixing the end of the cylinder 43 to the side wall 41.

At the control end a closure disc 61 is provided for the end of cylinder 43 which end projects beyond the inner cylinder 48. Closure disc 61 has a coaxial ring-flange 62 fitting into cylinder 43 and secured to it by screws 62'. It has an external large coaxial ring-flange 63 hearing slidingly in bearing 64 having a bronze bushing 64, the bearing 64 beingmounted in vertical side plate 42. The inner face of the flange 62 provides a space 62 between it and the end of the inner cylinder 48 and its coverings to accommodate relative axial movement of the cylinders 43 and 48.

Means is provided for controlling the power to heat the cylinder 43, such as that shown in FIGS. 4, 5, 8 and 9. The means includes a lever to magnify the movement of the cylinder 43. An inclined arm 70 is pivoted to the framework at 71 (see FIGS. 8 and 9) for horizontal movement. It has a recess 72 therein in which is located a button 73. A movable contact strip of metal 74 overlies the recess and button and is secured at one end to the arm 70 as shown at 75. The arm lies against the face 63 of the axial flange 63 of cylinder 43. The end of arm 70 has a forked recess 70 through which freely passes an adjusting screw 76 threaded into side plate 42. Screw 76 has a head 76' between which and arm 70 is a compression spring 77. Side plate 42 has an opening 42 through which freely passes a screw 78 threaded in arm 70 and, therefore, moved by and with arm 70. The end 78 of screw 78 is connected to a suitable micro-switch (not shown in detail) in switch-unit 79 of which the fixed portion is effectively secured and positioned by said nonexpansible arm 80, thus to provide a switch contact fixed relative to the fixed end of cylinder 43. Preferably, said switch is functionally comparable to the switch 27 in FIG. 2, which operates a relay and relay-switch to control the power to the heating means. Detail of wiring is omitted.

Pick-off means is provided as a spring-pressed blade 81 urged against the cylinder 43 (FIG. 8). It is fixed in a longitudinal holder 82 pivoted in the side plates by coaxial pins 83. Spring means is provided to regulate the pressure of blade 81 on cylinder 43. Associated with the holder 62 is a disk 83' having arm 83" which is pressed by pin 84 mounted within adjusting screw 84' against internal spring 84" (FIG. 8).

To provide a guided path for a paper print or like work sheet to pass around cylinder 43, stationary guiding means is provided as shown in FIG. 7. Its function is to provide a slip surface to press the work sheet against cylinder 43 during its passage around the roll. To this end a sheet of low-friction material such as flexible polytetrafluoroethylene 85 is mounted with a stationary edge 86 in the vicinity of the cylinder so as to extend freely in the direction of rotation. Resilient cushioning means 87 has an edge 88 fixed with said edge 86. The cushioning means 87 has an edge 88 fixed with said edge 86. The cushioning means has its opposite parallel edge 89 fixed so that the extent of the cushioning means presses the slip sheet 85 onto the cylinder 43. Rigid means is provided for securing the edges of the cushioning means. Preferably, it is in the form of a cylindrically arcuate shell 90 to the exterior greater than and made of springy metal so as to fuction like a clamp over cylinder 43. FIG. 7 shows the arcuate shell 90 with said resilient cushioning foam 87 lining it and turned over the edges of the shell 90 to the exterior, to which it is clamped. The slip sheet 85 at its fixed end 86 also is turned over the turned-over foam sheet and reversed over a metal strip 91. Over the resulting tail end of the slip sheet is placed a clamping strip 91 which is secured by screws 92 entering shell 90. At the opposite edge of the shell 90, the slip sheet 85 has a freely extending edge 85' terminating beyond the foam edge 89, which latter is turned over the edge of shell 90 and secured by metal strip 94 held by screw 95 entering the shell. The shell 90 has at each end angle brackets 96 (FIG, 4) providing a downwardly extending web 97 which carries a pin 98 paralleling the axis to enter a recess 99 (FIGS. 6 and 8) in each of the side plates 41 and 42 thus to hold the shell 90 stationary.

The cylinder 43 with its bearings and the guiding means of FIG. 6, later described, are readily removed as a unit upwardlyfrom the side plates 41 and 42. The structure is the same at both ends, and is, therefore, described with respect to side plate 42 as shown in FIG. 8. Plate 42 has a rectangular recess open at the top defined by lines 101, 102 and 103, and a flaring opening above it defined by lines 104 and 105. The bearing 64 is circular and of diameter greater than the distance between the lines 101 and 103. Portions of the periphery are grooved so as to receive edges of the side plate defined by the lines 101, 102 and 103, the edge 102 being shown in FIG. 5.

Opposite the groove for the edge 102 the bearing is also grooved for receipt of a locking bar 107 to close the said recess. Bar 107, like its opposite companion 107' (FIGS. 3, and 8), swings upwarldy on pivot 108 mounted in brackets 109 and 110 secured by screws 111 to side plate 42. The end of bar 107 is cut off at 45 as shown at 112 to permit a limiting vertical position of the bar for lifting out the cylinder 43 and its bearings. The other end 113 of the bar 107 fits into the space above side plate 42 between upright brackets 115 and 116 secured to the sides of plate 42 by screws 117 (FIG. 3). A bolt 118 passes through the brackets 115 and 116 and the end 113 to lock the bearings in the recesses of the side plates.

In operation, a print designated by P in FIG. 6 is entered between the rotating cylinder 43 and the fixed end of the slip sheet 86 to travel around and in contact with heated cylinder 43 until it reaches the pick-off blade 81 to effect its discharge as indicated at P. The speed of rotation and the temperature are adjusted to the characteristics of the sheet P for its development.

The invention is not limited to the exemplary embodiments above described for the purpose of illustration, and it is to be understood that modifications and other embodiments are contemplated as falling within the scope of the appended claims.

I claim:

1. In apparatus of the class described a rotatable cylinder adapted to be heated and thermostatically controlled, comprising an inner metallic cylinder, a layer of insulating material on the outer side of said cylinder, an insulated winding of electrical resistance wire around said cylinder, a thin-walled outer metallic cylinder snugly fitting over said winding, said outer cylinder having an appreciable coefiicient of expansion, said inner and outer metallic cylinders being fixedly secured together at their first ends with their second ends unsecured to each other thereby to permit one cylinder freely to change in length relative to the other, an end closure for each of the two ends of the outer cylinder, and axial means projecting from the end closures for rotatably mounting the outer cylinder.

2. Apparatus according to claim 1 in which the inner cylinder is perforated.

3. Apparatus according to claim 1 including an electrical switch for controlling power to the electrical winding, said switch being constructed and arranged for operation by the thermal expansion and contraction of the outer cylinder, whereby the switch and the outer cylinder constitute a thermostat.

4. Apparatus according to claim 1 in which the coils of the winding are more concentrated in the vicinity of the ends of the cylinders to compensate for greater heat loss at said ends.

5. Apparatus for heat-treating flexible sheet material comprising a heatable rotary cylinder, means to rotate said cylinder in one direction, guiding means for forming a path for said sheet material around and in contact with said cylinder, said guiding means extending around an arcuate portion of said cylinder leaving an open arcuate portion of the cylinder for receiving and discharging sheet material, pick-off means for said sheet in contact with said open arcuate portion, said guiding means comprising a stationary cylindrically arcuate shell around said cylinder, a flexible guiding slip sheet exposed at the interior of said shell and in contact with said cylinder, said guiding sheet being fixed at one edge to an edge of the arcuate shell and extending freely in the direction of rotation of the cylinder at least to the opposite edge of said arcuate shell, and cushioning means carried by said shell urging said guiding sheet into contact with said cylinder.

6. Apparatus for heat-treating flexible sheet material comprising a heatable rotary cylinder, means to rotate said cylinder in one direction, guiding means for forming a path for said sheet material around and in contact with said cylinder, said guiding means extending around an arcuate portion of said cylinder leaving an open arcuate portion of the cylinder for receiving and discharging sheet material, pick-off means for said sheet in contact with said open arcuate portion, said guiding means comprising a stationary member spanning an arcuate portion of said cylinder, a flexible guiding slip sheet exposed at the interior of said member and vin contact with said cylinder, said guiding sheet being fixed at one edge to an edge of the stationary member and extending freely in the direction of rotation of the cylinder at least to the opposite edge of said stationary member, and cushioning means secured to the said two edges of the stationary member and in position to urge said guiding sheet to the limit in the direction to contact said cylinder.

7. Apparatus comprising a framework, a rotary cylinder mounted in said framework, means to heat said cylinder, means to rotate the cylinder, guiding means fixed to said framework for compelling sheet material fed tangentially to said cylinder to follow said cylinder in contact therewith, said guiding means comprising a flexible guiding sheet positioned to contact an arcuate portion of the cylinder, means fixing one edge of the guiding sheet to the framework at a location such that the sheet extends freely in the direction of rotation of the cylinder, said guiding means also comprising cushioning material urging said guiding sheet in a direction to contact said cylinder.

8. In apparatus of the class described having a framework and a rotary cylinder mounted in said framework for moving a sheet around and in contact therewith, guiding means for said sheet comprising a cylindrically arcuate metallic casing, cushioning means lining the interior of said casing, and a guiding sheet over the arcuate extent of said cushioning means, said guiding sheet being fixed at one edge to said casing and extending freely from said fixed edge in the direction of rotation of said cylinder at least to the edge of said cushioning means, the diameter of said casing being sufliciently greater than the diameter of said cylinder to permit fixing the guiding means to said framework and mounting the guiding means around said cylinder with the guiding sheet in resilient contact with said cylinder.

9. Apparatus for heat-treating sheet material comprising in combination a framework, a rotary cylinder adapted to be heated, and guiding means for directing sheet material in a path around and in contact with said cylinder,

said cylinder being thermally expansi'blein the axial direction on heating, means to rotate the cylinder, bearing means to mount one end for rotation fixedly to said framework, bearing means permitting axial movement of the other end of the cylinder 'by thermal expansion, switchcontrolled electrically powered means within the cylinder to heat the cylinder, a power-controlling switch for said heating means, said switch being operated to cut ofi the power at a predetermined extent of expansion of the cylinder and to cut in the power at a predetermined contraction of the cylinder, said guiding means comprising a flexible guiding slip sheet in stationary contact with said cylinder, said guiding sheet having one edge fixed relative to the framework and extending from said edge freely in the direction of rotation, and stationary cushioning means urging said guiding sheet to the limit in the direction to contact said cylinder.

10. Apparatus according to claim 9 in which said guiding means comprises a rigid member spanning an arcuate portion of the cylinder with two opposite edges close to the cylinder, said cushioning means being secured to said two edges, and said guiding sheet being secured to one of said edges over said cushioning means and extending freely at least to the opposite edge and over said cushioning means.

References Cited by the Examiner UNITED STATES PATENTS 1,594,158 7/1926 Else 219-.512 1,605,027 11/1926 Himes 236101 X 1,612,270 12/1926 Duffie -39 3,012,141 12/1961 Thomiszer 25065.1 3,027,285 3/1962 Eisner et a1. 219-470 3,032,811 5/1962 Knowland et a1. 219471 3,176,113 3/1965 Eckerfeld ct a1 21 9-512 ANTHONY BART'IS, Acting Primary Examiner.

RICHARD M. WOOD, Examiner.

L. H. BENDER, Assistant Examiner. 

1. IN APPARATUS OF THE CLASS DESCRIBED A ROTATABLE CYLINDER ADAPTED TO BE HEATED AND THERMOSTATICALLY CONTROLLED, COMPRISING AN INNER METALLIC CYLINDER, A LAYER OF INSULATING MATERIAL ON THE OUTER SIDE OF SAID CYLINDER, AN INSULATED WINDING OF ELECTRICAL RESISTANCE WIRE AROUND SAID CYLINDER, A THIN-WALLED OUTER METALLIC CYLINDER SNUGLY FITTING OVER SAID WINDING, SAID OUTER CYLINDER HAVING AN APPRECIABLE COEFFICIENT OF EXPANSION, SAID INNER AND OUTER METALLIC CYLINDERS BEING FIXEDLY SECURED TOGETHER AT THEIR FIRST ENDS WITH THEIR SECOND ENDS UNSECURED TO EACH OTHER THEREBY TO PERMIT ONE CYLINDER FREELY TO CHANGE IN LENGTH RELATIVE TO THE OTHER, AN END CLOSURE FOR EACH OF TWO ENDS OF THE OUTER CYLINDER, AND AXIAL MEANS PROJECTING FROM THE END CLOSURES FOR ROTATABLY MOUNTING THE OUTER CYLINDER. 